Investment Securities - Additional Information (Detail) (USD $)	3 Months Ended
	Mar. 31, 2014 Security Investment	Mar. 31, 2013	Dec. 31, 2013
Investments Debt And Equity Securities [Abstract]
Fair value of investments	$ 126,059,000		$ 145,017,000
Fair value of investments, Percentage	61.30%		72.50%
Sustained decline in market value considered Impairment, period	12 months
Number of investment securities	4
Investment securities in continuous unrealized loss position, positions temporarily impaired	87
Other-than-temporary impairment losses recognized in accumulated other comprehensive income	0	0
Proceeds from sales of securities available-for-sale	649	200
Available-for-sale securities, gross realized gains	95	14
Available-for-sale securities, gross realized losses	3	0
Assets pledged to secure United States Government and other public funds and for other purposes	$ 65,030,000		$ 65,339,000